The present invention relates, in general, to an improved surgical biopsy instrument and, more particularly, to a lockout mechanism for use in a surgical biopsy instrument.
The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense interest in the medical community. Non-invasive methods for examining tissue and, more particularly, breast tissue include palpation, X-ray imaging, MRI imaging, CT imaging, and ultrasound imaging. When a physician suspects that tissue may contain cancerous cells, a biopsy may be done using either an open procedure or in a percutaneous procedure. In an open procedure, a scalpel is used by the surgeon to create an incision to provide direct viewing and access to the tissue mass of interest. The biopsy may then be done by removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). In a percutaneous biopsy, a needle-like instrument is inserted through a very small incision to access the tissue mass of interest and to obtain a tissue sample for examination and analysis. The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less disruption of associated tissue and nerves and less disfigurement. Percutaneous methods are generally used in combination with imaging devices such as X-ray and ultrasound to allow the surgeon to locate the tissue mass and accurately position the biopsy instrument.
Generally there are two ways to percutaneously obtain a tissue sample from within the body, aspiration or core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. Application is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors and no single procedure is ideal for all cases.
A number of core biopsy instruments which may be used in combination with imaging devices are known. Spring powered core biopsy devices are described and illustrated in U.S. Pat. Nos. 4,699,154, 4,944,308, and Re. 34,056. Aspiration devices are described and illustrated in U.S. Pat. Nos. 5,492,130; 5,526,821; 5,429,138 and 5,027,827.
U.S. Pat. No. 5,526,822 describes and illustrates an image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument which takes multiple tissue samples without having to re-puncture the tissue for each sample. The physician uses this biopsy instrument to xe2x80x9cactivelyxe2x80x9d capture (using the vacuum) the tissue prior to severing it from the body. This allows the physician to sample tissues of varying hardness. The instrument described in U.S. Pat. No. 5,526,822 may also be used to collect multiple samples in numerous positions about its longitudinal axis without removing the instrument from the body. A further image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in commonly assigned U.S. application Ser. No. 08/825,899, filed on Apr. 2, 1997 and in U.S. Pat. Nos. 6,007,497; 5,649,547; 5,769,086; 5,775,333; and 5,928,164. A handheld image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462. The instrument described therein moves drive motors and other electronic components into a control unit separate from and remotely located from the biopsy probe. Biopsy probe cutter rotational and translational motion is transferred from the motors in the control unit to the biopsy probe via flexible coaxial cables. This arrangement greatly improves the cleanability of the reusable hardware that remains in close proximity to the biopsy site as well as improves the life and durability of the electric motors and electronic components now remotely located from the biopsy probe. The biopsy instrument described and illustrated in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462 was designed primarily to be a xe2x80x9chand heldxe2x80x9d instrument to be used by the clinician in conjunction with real time ultrasound imaging. Several image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instruments are currently sold by Ethicon Endo-Surgery, Inc. under the Trademark MAMMOTOME(trademark).
The majority of breast biopsies done today, however, utilize an x-ray machine as the imaging modality. Using x-ray requires that the biopsy instrument be affixed to the x-ray machine by some type of bracket arrangement. Since the biopsy instrument is fixed to a portion of the x-ray machine there is now a need for a means to conveniently rotate the biopsy probe once it is advanced into the breast in order to accurately position the vacuum port at the distal end of the probe.
In U.S. Pat. No. 5,649,547 a biopsy device is disclosed which includes a drive assembly containing a stored energy probe xe2x80x9cfiringxe2x80x9d mechanism. This firing mechanism is used by the clinician to rapidly advance the biopsy probe piercing element into the patient during a biopsy procedure, which is necessary to penetrate the dense tissue comprising many lesions. Also disclosed in U.S. Pat. No. 5,649,547 is a biopsy device which includes a drive assembly containing a stored energy probe xe2x80x9cfiringxe2x80x9d mechanism. This firing mechanism is used by the clinician to rapidly advance the biopsy probe piercing element into the patient during a biopsy procedure, which is necessary to penetrate the dense tissue comprising many lesions. The firing mechanism in U.S. Pat. No. 5,649,547 includes a probe firing safety system intended to minimize the risk of the biopsy probe being fired prematurely or accidentally. The system includes a xe2x80x9cpiercexe2x80x9d button and a xe2x80x9csafetyxe2x80x9d button, both of which are utilized in the process of firing the biopsy probe piercing element into the patient. The pierce button is attached to a latch, which interfaces with the stored energy firing mechanism. By depressing the pierce button, stored energy in the firing mechanism is released causing the biopsy probe to rapidly advance distally into the patient. The safety button is attached to a rod and is free to slide in a linear fashion. In the xe2x80x9conxe2x80x9d position, the rod is placed in interference with the travel of the pierce button thus preventing accidental firing of the biopsy probe. Conversely, the safety button can be placed by the clinician in the xe2x80x9coffxe2x80x9d position, moving the rod clear of the pierce button and allowing for full travel of the pierce button to effect the firing of the biopsy probe.
It would, therefore, be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, breast biopsy instrument which may be conveniently mounted to an x-ray machine, and incorporate into it a safety system that is located in an area that can be easily viewed and accessed by the user irrelevant of the position of the user to the instrument during a biopsy procedure. It would further be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, breast biopsy instrument which may be conveniently mounted to an x-ray machine in which the safety system is biased to the xe2x80x9conxe2x80x9d or safe position, to eliminate the risk of the safety being unknowingly positioned to the xe2x80x9coffxe2x80x9d position. It would further be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, breast biopsy instrument which may be conveniently mounted to an x-ray machine in which the safety system operates in a non-linear motion, is biased to the on or safe position, and is located immediately adjacent to the pierce button further improving the convenience of activating the firing mechanism to the user while reducing the risk of the biopsy probe being fired unintentionally.
The present invention is directed to a biopsy instrument including a probe assembly, a base assembly and a drive assembly. The probe assembly including a cutter assembly and a piercer assembly slideably attached to the cutter assembly. The base assembly is detachably mounted to the probe assembly wherein the base assembly includes a firing fork operatively connected to the piercer assembly, a spring operatively connected to the firing fork wherein the spring opposes movement of the firing fork in a proximal direction, a trigger mechanism adapted to move the firing fork in a proximal direction, a latch mechanism adapted to hold the firing fork in a first position a release mechanism adapted to release the latch mechanism and a lockout mechanism adapted to prevent the release mechanism from releasing the latch mechanism. The drive assembly including a flexible drive shaft which is operatively connected to the cutter assembly.
The present invention is further directed to a biopsy instrument including a probe assembly, a base assembly and a drive assembly. The probe assembly including a cutter assembly and a piercer assembly. The cutter assembly including a cutter and a gear mechanism adapted to move the cutter. The piercer assembly being slideably attached to the cutter assembly. The base assembly is detachably mounted to the probe assembly wherein the base assembly includes a firing fork removably attached to the piercer assembly such that movement of the firing fork in a distal direction moves the piercer assembly in a distal direction, a spring operatively connected to the firing fork, the spring being adapted to oppose movement of the firing fork in a proximal direction, a trigger mechanism operatively connected to the firing fork, the trigger mechanism being adapted to move the cutter in a proximal direction, a latch mechanism operatively connected to the firing fork to hold the firing fork in a first, proximal position, a release mechanism adapted to release the latch mechanism when the release mechanism is moved in a first direction, a lockout mechanism adapted to prevent the release mechanism from moving in the first direction, the lockout mechanism including a spring biased rotatable plate. The spring biased rotatable plate includes a first spring wire, a second spring wire wherein the first and second spring wires define a first opening in the plate, a handle affixed to the plate and projecting from the base assembly. The drive assembly including a flexible drive shaft operatively connected to the gear mechanism.